This invention relates to experimental flow channel blocks and the method of making inserts of curable plastic material to change the size and shape of the flow channels.
In the design and production of experimental flow channel blocks and other metal components the optimum contour of the flow channel has been provided by cut and try machining. This is an expensive and time consuming process. Machining metal inserts to change the flow channel contour has also not been satisfactory because of the time required and the difficulty in machining the inserts to fit in the flow channels. Utilizing a curable plastic material to produce a tire mold is disclosed in U.S. Pat. No. 5,449,483 where the plastic is used as a resin backing for a reinforced shell formed on a model. Also in U.S. Pat. No. 4,858,881, a tire mold surface is provided by pouring an epoxy over a tire sidewall in a mold box. Patterns have also been used in making molds for casting metal products, however, none of these methods have suggested an inexpensive method of modifying a flow channel to determine the optimum contour for the flow of extrudates, especially those used for tire components.
The present invention is directed to a method of providing a flow channel of the optimum size and shape in a metal flow channel block with a minimum cost and in a short period of time. The existing flow channel in the flow channel block is filled with a blank of an easily machinable material, such as machinable wax. This blank hardens and after removal from the flow channel recess may be easily machined to provide a pattern having a size and shape believed to have the optimum contour for a particular operation. A release agent may be applied to the pattern which may then be placed in the flow channel with a thermally conductive epoxy casting resin. After the epoxy is cured and hardened to form an insert, the pattern is removed. The blank may also be an easily machinable block of material of a different shape than the flow channel.
In accordance with one aspect of the invention, there is provided a method of changing the contour of a first recess in a body of solid material to provide a second recess characterized by;
(a) shaping a pattern having the size and shape of the second recess,
(b) placing the pattern and a curable plastic material in the first recess,
(c) hardening the curable plastic material to form an insert; and
(d) removing the pattern from the insert to form the second recess.
In accordance with another aspect of the invention, there is provided a flow channel block having a first recess characterized by an insert of curable plastic material in said first recess, a second recess in said insert providing a flow channel having a revised contour and being formed by a pattern placed in said first recess with said curable plastic material of said insert in a plastic condition and removed after hardening of said curable plastic material.